The reason that I ask this question is because I have been fighting a drivablilty problem for 2 weeks. I made the mortal sin of making 4 changes carb wise at one time. I put one of Curt's intakes on, dejetted from a 182.5 to a 175, changed the float level and put a new Yamaha enricher cable on. That is when it all started, it startes and idle fine, from 15 mph up to about 40 in 3rd gear it is ruff as a cob. I shift into 4th and can slow down to 35 and it is pretty smooth but still not right. As soon as I get above 50 it runs great. I want to add that I used a fuel container that I have used to run other things with their tanks off. I used it without a filter to try and set the float level with the carb of the bike and it may have been contaminated with water. Except for the cable I have put the carb back to the way it was before all this started and reinstalled my stock intake.

I want to say to all that know Curt's intake had nothing to do with my carb issue, because it does exactly the same with booth intakes and yes I have leak checked and am sure no intake leaks.

I am at a point that I don't want to spend any more money on this carb. I think I would like to try another good clean carb before I make the jump to the HSR 42. I have had this carb off and on 5 times in the last week alone. I have been burning up the phone with Curt and neither one of us can figure this one out. He has offered to go thru this carb if I send it to him, but he also thinks I should go to the 42mm and not look back.

I am 100% sure that I have not missed any thing during assembly. I am not saying that I can not and have not missed things before, I'm just saying that I didn't miss it 5 times in a row. I am hoping that some one out there has seen this or had this issue and was able to fix it.

I am sorry this is so long but I wanted every one to have the facts before guiding me to the right decision. Y'all are great and a special thanks to Curt for the help and putting up with me.

Joel

which jet kit are you using? And what yr bike? Did you check the float level with carb on bike and the bike on a lift? Did you have to do the choke knob mod to ensure that it is closing fully? Did you turn up the idle speed with the idle adjuster? Are you running baffles? Did you check the slides diaphragm for any tears, might have to give it a little stretch as ya check to see if there are any real small holes. Is the pilot jet the stock #35 Mikuni?

my setup is similar to yours. I run the mikuni 167.5 at 4th clip.
Works great for me.

Erbman - to answer your question, I guess it is a Barons, it has a Barons needle on the 4th groove with no washers, 182.5 mikuni MJ, 35 yamaha PJ, all other replacable air jets, o-rings and diaphrams was bought from yamaha and replaced 2 1/2 months ago. I did the rebuild and every replacable part except the body and slide was replaced. The carb has been extensivly cleaned with carb cleaner and shop air 6 times since I bought the bike.

Curt and I agree that the problem is in the low speed side of the carb from just off idle to about 1/4 throttle. I beleive that the problem is not with any replacable part, but within the body of the carb. The passages under the PJ seem to hav some sort of blockage that I can not explain. I would think the way the body is manufactured that the passages under the jets should be open and clear. The are drillings in a cast body, with that said, I think there are restrictions of some kind in the PJ circut that is restricting the fuel flow other than the jets.

I have said this before that the bike only got 40 miles put on it in the 14 or 15 months before I got it. Motorcycles can not be any different that the aircraft that I work on, setting idle (not used) causes issues that can be very costly to fix. High utilazation, flying the fool out of it is a good thing, does not give the grimelins a chance to take hold.

Ok, so then the only way to clean a carb with that background is with a good soaking in a carb cleaning solution. It's probably too far gone with a lacquer build up to get it cleaned any other way. It needs to soak then air sprayed out. Spray carb cleaner, carb fuel treatment cleaners are not going to give a good soaking on a lacquer build up that is hard as nails

The needle set-up without the washer under the spacer is step 3.5, it needs the washer to bring it to a full step 4. Also suggest to turn the idle adjuster in 2 full turns, then set the pilot screw to 2.25 to 2.5 turns to start. Expect the idle to be high, especially after riding for 15, 20 min, then, at that point readjust the idle adjuster to proper idle rpm's.

Turning the idle adjuster in will increase the rpms for the start up, which with the air going thru the venturi (throat) of the carb should also help to create a slightly stronger vacuum to pull fuel up thru the internal channels of the carb.

I've seen this too many times before, where a lot of people forget to use the idle adjuster and try to adjust idle strictly with the pilot screw. they work hand in hand. If the butterflys are kept too closed, there is not enough air passing thru the venturi to create the vacuum to pull fuel thru the internal passages.

Thanks for the advice, I will give it a try. I just spoke to a guy that I used to drag race with and he said that he has a HSR45 that I could have, but it needs a float bowl (dented bad). Curt told me one of the members runs a 45 on his 1600 so it should work.

Thanks All,

Joel

I have had a HSR45 on my 03 for several years with no problems. Runs smooth and strong...........

i just seen a post on the rsr forum on the stock cv40 and hsr42 with dyno results. while the hp was just about the same (less than 1 hp) the torque was a little bit better but not by much at all. but what was very interesting is that both hp and tq came on much faster on the hsr42

Ok, I made the decision to go with the HSR 42 and bought one. Curt has sent me the info and details to put my TPS on it. Depending on when I get it, I sould have it done within a week. My bike is still ridable so I'm not missing that much riding, I am using it for my comute as much as I can. I have a friend who will machine the plate mount for me.

Your gunna love yhat crispy throttle I put a hsr45 on over the winter and I love it. Only down fall is no carb heater so here in Michigan cold starts can be a pain in the early spring and late fall.